I've got nothing more.

Most references, in regard to barrels, cite early change of muzzle crown from 'flat' crown to a crown with radius, (during model 1892 production), and, (during model 1898 production), a change of barrel breech-face from square-cornered to beveled-cornered.

Frank Mallory, "Krag Rifle Story", reports the change in chamber dimensions during 1899. (I am sure Mallory found a factual basis for this).

Precision chamber casts of a model 1896 barrel and a late model 1898 barrel would be interesting to compare.

I am sure measuring the dimensions of brass, fired in two such chambers, would have the additional variable of differences in free-travel (head-space) of the respective actions.

Note - In the drawings used by Mallory, measurements were taken from the front of the cartridge rim. Rim thickness is absent.

Drawings based on SAAMI dimensions include the cartridge rim thickness, of .064".